Inpatient versus outpatient shoulder arthroplasty outcomes: A propensity score matched risk-adjusted analysis demonstrates the safety of outpatient shoulder arthroplasty.

OBJECTIVES

Beginning January 1, 2021 total shoulder arthroplasty (TSA) was removed from the Medicare (U.S national healthcare for patients ≥ 65years of age) inpatient-only list. Furthermore, there is limited data comparing outpatient and inpatient TSA among recent contemporary large population databases. This study aimed to analyze shoulder arthroplasty outcomes between inpatient and outpatient procedures at the national level.

METHODS

The American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database was utilized (2015-2019). Cases with a current procedural terminology of 23472 indicative of primary TSA and reverse total shoulder arthroplasty were included (N = 22,452). Outcomes were then analyzed in two approaches: unmatched analysis and propensity score matched risk-adjusted analysis.

RESULTS

Overall, 9.7% (N = 2,185) of cases were performed outpatient and 90.3% (N = 20,357) of cases were performed inpatient. The rate of outpatient procedures has been steadily increasing (2015: 8.3%, 2016: 14.7%, 2017: 15.8%, 2018: 26.5%, 2019: 34.6%; P < 0.001). Outpatients were more likely to be male (50.7% vs. 43.7%) and younger (age < 65; 37.0% vs. 27.9%) and less likely to be ASA class 3 or 4 (49.5% vs. 58.3%). Outpatients had fewer comorbidities including obesity (46.1% vs. 51.9%), hypertension (60.5% vs. 67.4%), diabetes (15.1 vs. 18.2%), chronic obstructive pulmonary disease (4.8% vs. 7.0%), bleeding disorders (1.3% vs. 2.5%), or chronic steroid use (3.5% vs. 5.0%; all P < 0.001). In a non-risk matched analysis of outcomes, outpatient procedures displayed lower rates of any adverse event (3.5% vs. 5.3%; P < 0.001), minor adverse events (1.5% vs. 3.0%; P = 0.001), and readmission (2.2% vs. 2.8%; P = 0.025). Following a propensity score matched analysis, two risk matched cohorts of outpatient (N = 2,172) and inpatient (N = 2,172) procedures were identified. Subsequent analysis of outcomes revealed no significant differences in outcome metrics between risk-matched outpatient and inpatient procedures.

CONCLUSIONS

From 2015 to 2019, there has been a four-fold increase in the proportion of outpatient shoulder arthroplasty cases in the ACS-NSQIP database. This study shows that outpatient shoulder arthroplasty may be safely performed in a select cohort of patients without increased risk of adverse events. After adjusting for comorbidities, there were no differences in clinical outcomes or rates of adverse outcomes between inpatient and outpatient shoulder arthroplasty.

LEVEL OF EVIDENCE

Retrospective Observational Study, Level IV.